Hydraulic intensifier

ABSTRACT

A hydraulic intensifier interposed between an accumulator and a source of pressure fluid including a hydraulic pump, comprising a housing with small and large diameter cylindrical bores therein, a small diameter piston reciprocatably engaged in the small diameter cylindrical bore to form a pressure chamber for amplifying fluid pressure from the source of pressure fluid, a large diameter piston reciprocatably engaged in the large diameter cylindrical bore to operate the small diameter piston, and a control valve means incorporated within the large diameter piston to control reciprocation of the large diameter piston, thereby, easy assembling work is realizable with a small number of parts and accurate operation of the device is obtainable, and above all, the time necessary to charge the accumulator with fluid pressure can much be reduced.

United States Patent Jan. 20, 1970, Japan, No. 45/6323 [54] HYDRAULIC INTENSIFIER 5 Claims, 4 Drawing Figs.

[52] U.S. Cl 417/225, 417/349, 91/422 [51] Int. Cl ..F04b 17/00, F04b 35/00, F15b 11/08 [50] Field of Search 60/54.5 l-lA, 54.6 HA, 54.5 A, 54.6 A; 91/422, 460; 417/225, 226, 349

Primary ExaminerEdgar W. Geoghegan Assistant ExaminerA. M. Zupcie Art0rney Berman, Davidson & Bennan ABSTRACT: A hydraulic intensifier interposed between an accumulator and a source of pressure fluid including a hydraulic pump, comprising a housing with small and large diameter cylindrical bores therein, a small diameter piston reciprocatably engaged in the small diameter cylindrical bore to form a pressure chamber for amplifying fluid pressure from the source of pressure fluid, a large diameter piston reciprocatably engaged in the large diameter cylindrical bore to operate the small diameter piston, and a control valve means incorporated within the large diameter piston to control reciprocation of the large diameter piston, thereby, easy assembling work is realizable with a small number of parts and accurate operation of the device is obtainable, and above all, the time necessary to charge the accumulator with fluid pressure can much he reduced.

PATENTEB JAN 4397? 3am u 0F 4 POWER ACCESSORIES Fig. 4

ATSZ/M/ ATTORNEYJ,

HYDRAULIC INTENSIFIER The present invention relates to a hydraulic intensifier to amplify fluid pressure supplied from a source of fluid pressure and to store the amplified fluid in an accumulator, and more particularly to a novel intensifier to be utilized for a hydraulic system to operate a plurality of hydraulically actuated devices.

A first important object of the present invention is accordingly to provide a hydraulic intensifier which supplies fluid pressure from a source of fluid pressure directly to an accumulator until the source of fluid pressure produces fluid pressure of a predetermined value, and then, amplifies the fluid pressure of the predetermined value, storing the fluid pressure amplified up to a desired value in the accumulator, thereby, reducing the time necessary to charge the accumulator with fluid pressure.

A second important object of the present invention is to provide a hydraulic intensifier comprising a housing incorporated with a large diameter cylindrical bore and a small diameter cylindrical bore, a small diameter piston reciprocatably engaged in the small cylindrical bore to form a first pressure chamber which amplifies fluid pressure from a source of fluid pressure and delivers the amplified fluid pressure into an accumulator, a large diameter piston reciprocably engaged in the large diameter cylindrical bore and constantly being in contact with said small diameter piston at one end and further provided with a bore inside thereof along its axial center, said large diameter piston urging the small diameter piston against fluid pressure acting on the small diameter piston by means of fluid pressure from the source of fluid pressure, and control valve means installed reciprocatably within the bore of the large diameter piston to control movements of the large diameter piston is response to fluid pressure from the source of fluid pressure, said large and small diameter pistons being separately engaged in the cylindrical bores respectively prepared within the housing, thereby, precise corresponding cocentricity is not required between the large and small diameter pistons and yet high accuracy is obtainable with easy assembling work.

A third important object of the present invention is to provide a hydraulic intensifier having the above described characteristics, wherein a cylinder-shaped resilient member made of rubber or rubberlike materials covers up one end of the large diameter piston, which is the opposite to the one in constant contact with one end of the small diameter piston, to absorb effectively impulsive force the large diameter piston produces against the inner wall of the housing at the reciprocation thereof, the structures of the device as well as the resilient member rendering high durability of the resilient member.

A further important object of the present invention is to provide a hydraulic intensifier having the above described characteristics, wherein the control valve means is operated so smoothly within the large diameter piston as to assure accurate reciprocation of the large diameter piston.

It is yet an important object of the present invention to provide a hydraulic intensifier having the above described characteristics, wherein the device is designed to require a small number of parts with a simple and compact construction.

Other objects and advantages of the present invention the present invention will be made more apparent in the following description, particularly when considered in connection with the accompanying drawings, in which;

FIG. 1 is a view of a longitudinal cross section of an embodiment in accordance with the present invention at the initial operation stage thereof;

Hg. 2 is a view of a longitudinal cross section of the embodiment as shown in FIG. 1 but at the final operation stage thereof;

FIG. 3 is a view of a longitudinal cross section of another embodiment in accordance with the present invention at the initial operation stage thereof;

FIG. 4 is a view of a longitudinal cross section of the embodiment shown in FIG. 3 but at the final operation stage thereof.

. fier mainly comprises a housing 1, a small diameter piston 5, a

large diameter piston 6,, a control valve means 8 regulating the reciprocation of the large diameter piston 6, and a return spring 10 to control the operation of the control valve means The housing 1 is illustrated as having a small diameter cylindrical bore 2 and a large diameter cylindrical bore 3. The small diameter cylindrical bore 2 has the small diameter piston 5 reciprocatably engaged therein and forms a pressure chamber 4 which is connected at one side to a pump P through a port 51 and a check valve 52 and at another side to an accumulator 43 through a port 41 and a check valve 62. The large diameter cylindrical bore 3 has the large diameter piston 6 reciprocatably engaged therein and forms a pressure chamber 19 which is selectively connected with the pump P through a port 24, and an exhaust chamber 1 18 in communication with a reservoir R through a port 40.

In the initial operation, the large diameter piston 6 engaged within the large diameter cylindrical bore 3 touches at its left shoulder 14 to the annular surface 16 of a plug 15 threaded in the housing 1, and at the right shoulder 17 thereof to the small diameter piston 5. The control valve means 8 is reciprocatably installed within a bore 7 drilled in the large diameter piston 6 along the axial center thereof, said control valve means 8 being for forwarding and reversing the large diameter piston 6. One end of the control valve means 8 is positioned at the right end portion of the large diameter piston 6, the other end being constantly urged rightward in the figure by the return spring 10 secured on the left shoulder 12 of the control valve means 8 at one end thereof with the other end secured on a retainer 13 fixed on the left end of the large diameter piston 6. In the initial operation, the control valve means 8 keeps the right end 9 thereof in touch with the right end inner wall 11 of the large diameter piston 6.

A first port 20 drilled in the large diameter piston 6 along the radius line thereof connects a chamber 21 to the pump P through a groove 45 and passageways 46 and 53 as the control valve means 8 moves leftward. A second port 22 is prepared to connect the chamber 21 to the pump P when the control valve means 8 is in the initial operation as well as in the leftward movement. The control valve means 8 being incorporated within the large diameter piston 6, the second port 22, thus, connects furthermore the chamber 21 to the exhaust chamber 118, which is in communication with the reservoir R, through passageways 53, 46 and the groove 45, when the large diameter piston 6 reaches its rightward stroke end keeping the control valve means 8 in its leftward stroke end as illustrated in FIG. 2. A third port 23 produces connection between the chambers 21 and 118 through the passageways 53, 46 and the groove 45 when the control valve means 8 returns to the original position thereof, that is to say when it makes the rightward movement.

A chamber 28 formed between an inner circumferential groove of the large diameter piston 6 and the outer circumferential wall of the control valve 8 is connected to the pump P through a vertical hole 27 of the large diameter piston 6, a chamber 26 formed between an outer circumferential groove of the large diameter piston 6 and the inner circumferential wall of the housing 1, a chamber 25 formed between an inner circumferential groove of the housing 1 and the outer circumferential wall of the large, diameter piston 6, and the port 24. When the control valve means 8 is in the original position as illustrated in FIG. 1, the chamber 28 is closed to a chamber 30 by the fit between the back-portion 50 of the control valve means 8 and a land 29 of the large diameter piston 6, said chamber 30 being formed between the inner circumferential groove of the large diameter piston 6 and the outer circumferential groove of the control valve means 8. The leftward movement of the control valve means 8 opens the chamber 28 to the chamber 30. The chamber 30 is open constantly to the chamber 19 through a slant passageway 31 drilled in the large diameter piston 6 and also open to a chamber 34 formed with the inner circumferential groove of the large diameter piston 6 through a passageway 33 when the control valve means 8 is in the original position thereof. The leftward movement of the control valve means 8 closes the chamber 30 to the chamber 34 by the fit between a land 32 of the large diameter piston 6 and a land 36 of the control valve means 8. The chamber 34 is in communication with the reservoir R through a passageway 35 drilled in the large diameter piston 6 and and the chamber 118 and, on the other hand, is open to a chamber 37, on which the return spring 10 is secured, through a passageway 39 made along a radius line of the control valve means 8 and a passageway 38 made along the axial line of the control valve means 8.

Described below is the operation in detail of the preferred embodiment of the present invention, the construction of which has heretofore been explained in the above.

Reference is made to FIG. 1, the pump P delivers pressure fluid to the ports 51 and 24 of the hydraulic intensifier. The pressure fluid supplied to the port 51 through the check valve 52 gets in the chamber 4 and, then, flows directly into the accumulator 43 through the port 41 and the check valve 62. The bypassed flow of pressure fluid to the port 24 runs through the chamber 25, the second port 22, the groove 45, the passageways 46 and 53, and the chamber 21 to act on the right area of the control valve means 8. At the same time, the fit between the shoulder 50 of the control valve means 8 and the land 29 of the large diameter piston 6 blocks the hydraulic flow of the pressure fluid supplied into the chamber 28 through the port 24, the chambers 25 and 26, and the passageway 27.

When the pressure fluid within the chamber 21 as well as the chamber 4 reaches the predetermined value, the control valve means 8 starts moving leftward against the force of the return spring 10. This produces the fit between the lands 36 and 32 to close the connection between the chamber 30, which opens to the chamber 19, and the chamber 34, which is in communication with the chamber 118. As the control valve means 8 is further moving leftward, the fit between the shoulder 50 of the control valve means 8 and the land 29 gets off each other to lead the hydraulic flow within chamber 28 to the chamber 19 through the chamber 30 and the passageway 31. Accordingly, as the control valve means 8 is moving leftward, the large diameter piston 6 starts moving rightward urged by the pressure fluid supplied into the chamber 19. At the same time, pressure fluid flows into the chamber 21 through the first port 20 to help maintaining the leftward movement of the control valve means 8. The rightward thrusting force of the large diameter piston 6 urges the small diameter piston S rightward to supply the accumulator 43 with such pressure fluid as of a higher pressure value than that of the pump pressure.

When the pistons and 6 reaches the right stroke end as illustrated in FIG. 2, the inner circumferential wall of the housing 1 closes the first and second ports 20 and 22. Thus, pressure fluid from the pump P is prevented from entering into the chamber 21 through the port 24. The chamber 21 becomes now open to the chamber 118 by way of the passageways 53 and 46, the groove 45, the second port 22, and the enlarged section 54. The pressure fluid within the chamber 21 consequently returns to the reservoir through the port 40 and the return spring urges the control valve means 8 rightward. At this moment, the third port 23 works to assure the displacement of the pressure fluid from the chamber 21. Now the fit between the lands 32 and 36 comes off to lead the pressure fluid in the chamber 19 to the reservoir R by way of the passageway 31, the chamber 30, the passageway 33, the chamber 34, the passageway 35, the chamber 118, and the port 40. The large diameter piston 6 returns to the original position by the leftward thrusting force of the small diameter piston 5, the leftward thrusting force being produced by the pressure fluid in the chamber 4.

In the hydraulic intensifier in the present invention, pressure fluid delivered to the port 24 from the pump P moves, as in the above described operation, the control valve means 8 leftward to urge again the large diameter piston 6 rightward. Consequently, the hydraulic intensifier keeps the fluid pressure amplifying operation until the accumulator 43 is charged to its desired pressure.

In the above described embodiment, the small and large diameter pistons 5 and 6 are separately provided within the respective cylindrical bores 2 and 3 of the housing 1, thereby easy assembly works of the small and large diameter pistons 5 and 6 into the housing 1 are realized, and yet accurate working of the intensifier is maintained.

Furthermore, in the above described embodiment, accurate operation of the control valve means 8 is obtained by the help of the first port 20, an inlet port, and the third port 23, an outlet port, prepared in addition to the second port 22 to receive the pressure fluid from the port 24 and to drain the pressure fluid into the exhaust chamber 118.

Another embodiment of the present invention is to be described below with reference to FIG. 3 and 4, in which similar reference numerals as in FIGS. 1 and 2 indicate such parts as of same or substantially similar functions. The feature in this embodiment is that a cylindershaped resilient member 101 made of rubber or rubberlike materials covers the leftend portion 6a of the large diameter piston 6. The cylinder shaped resilient member 101 is provided with an orifice 104 and touches at the left end thereof to the inner surface of the plug 15' threaded in the left end of the housing 1'. The orifice 104 is to connect the chamber 19 to a chamber 18 when the resilient member 101 is tightly pressed onto the inner surface of the plug 15. Passageways 6b and 6c drilled in the large diameter piston 6 along radius lines thereof are additionally made for the manufacturing convenience in drilling the passageways 35 and 31, and are sealed with balls b and 0.

Operation of the second embodiment is the same as that of the first embodiment; in the case of the second embodiment, however, the impulsive force which the large diameter piston 6', produces against the plug 15' is well absorbed by the shockabsorbing effect of the cylinder shaped resilient member 101 and compression of the pressure fluid within the chamber 18, the impulsive force being produced when the large diameter piston 6' returns leftward after amplifying the fluid pressure inside the chamber 4' by the rightward movement thereof through the controlling work of the control valve means 8'.

When the large diameter piston 6' starts its rightward movement, the connection between the chambers 18 and 19 prevents the cylindershape resilient member 101 from sucking on the inner face of the plug 15'. The large diameter piston 6, thus, leaves off the plug 15 easily and makes smoothly its rightward movement.

As clearly described above, in the second preferred embodiment, the reciprocation of the large diameter piston 6' within the large diameter cylindrical bore 3' makes no impulsive touch of the large diameter piston 6 direct to metal members such as the plug 15' by means of the cylinder shaped resilient member 101 which, also, absorbs effectively impulsive force between the large diameter piston 6' and the plug 15. Thus the noneffective stroke of the large diameter piston 6 is much reduced, and noises caused by the impact of the large diameter piston 6' against the plug 15' is eliminated. The compression of the hydraulic fluid within the chamber 18 helps the cylinder shaped resilient member 101 in absorbing the impulsive force of the large diameter piston 6 against the plug 15', the resilient member 101 being this provided with good durability.

While the remaining primed reference numerals in FIGS. 3 and 4 have not been shown in detail it should be understood that each has the same function as its unprimed counterpart described in the embodiment of FIGS. 1 and 2.

It will be understood that the present invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the present invention, as defined in the appended claims.

What I claim is:

1. In a hydraulic intensifier; a housing having therein a steppeddiameter cylindrical bore forming a small diameter bore portion connected to a first inlet conduit to receive fluid pressure from a source of fluid pressure and and outlet conduit to charge fluid pressure to an accumulator and a large diameter bore portion connected to a second inlet conduit to receive fluid pressure from the source of fluid pressure, said housing also including an exhaust conduit communicating with said large diameter bore portion, a stepped piston comprising a small diameter piston portion reciprocable within said small diameter bore portion to form a first pressure chamber for amplifying the fluid pressure supplied to said outlet conduit from said first inlet conduit and a large diameter piston portion reciprocatably engaged in said large diameter bore portion to form a second pressure chamber selectively in communication with said second inlet conduit and an exhaust chamber connected to said exhaust conduit, said large diameter piston portion including a bore drilled therein along the axial center thereof, a control valve means reciprocatably engaged in said bore within said large piston portion, a third pressure chamber formed between said control valve means and said last named bore, an inletoutlet port connecting said third pressure chamber alternately to said second inlet conduit and said exhaust chamber, a first passageway to communicate said second pressure chamber with said second inlet conduit, and a second passageway to connect said second pressure chamber with said exhaust chamber, said control valve means operating to close said second passageway and open said first passageway when the fluid pressure supplied to said third pressure chamber through said second inlet conduit and said inletoutlet port reaches a predetermined value, the operation causing the fluid pressure within said second pressure chamber acting on said large diameter piston portion to urge said small diameter piston portion to amplify the fluid pressure within said first pressure chamber, and said control valve means continuously operating to open said second passageway after connecting said third pressure chamber to said exhaust chamber through said inletoutlet port.

2. A hydraulic intensifier as set forth in claim 1, wherein said stepped piston is an integral piston having the small diameter piston portion and the large diameter piston portion formed therein.

3. A hydraulic intensifier as set forth in claim 1, wherein said stepped piston comprises a small diameter piston and a separate large diameter piston, said small and large diameter pistons being in constant contact with each other.

4. A hydraulic intensifier as set forth in claim 1, wherein said large diameter piston has a cylindershaped shock absorbing member made of resilient material at one end thereof, said cylindershaped shock absorbing member being provided with an orifice communicable with said second pressure chamber around the circumference thereof.

5. A hydraulic intensifier as set forth in claim 1, wherein there is provided at the sides of said large diameter piston an inlet port connecting said second inlet conduit to said third pressure chamber and an exhaust port connecting said exhaust chamber to said third pressure chamber.

UMTED STATES PATENT @FFHJE fiR'HWQATE GE RQHGN Patent No. 3,632,230 Dated January 4, 1972 Atsumi Ueda Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 10, "and", second occurrence, should read an Signed and sealed this 17th day of October 1972..

(SEAL) Attest:

EDWARD M.FLETCHER,JR. Attescing Officer FORM P0-1050 (10-69) USCOMM-DC eoavwpae Q U.S. GOVERNMENT PRINTING OFFICE: I969 O366-334. 

1. In a hydraulic intensifier; a housing having therein a stepped-diameter cylindrical bore forming a small diameter bore portion connected to a first inlet conduit to receive fluid pressure from a source of fluid pressure and and outlet conduit to charge fluid pressure to an accumulator and a large diameter bore portion connected to a second inlet conduit to receive fluid pressure from the source of fluid pressure, said housing also including an exhaust conduit communicating with said large diameter bore portion, a stepped piston comprising a small diameter piston portion reciprocable within said small diameter bore portion to form a first pressure chamber for amplifying the fluid pressure supplied to said outlet conduit from said first inlet conduit and a large diameter piston portion reciprocatably engaged in said large diameter bore portion to form a second pressure chamber selectively in communication with said second inlet conduit and an exhaust chamber connected to said exhaust conduit, said large diameter piston portion including a bore drilled therein along the axial center thereof, a control valve means reciprocatably engaged in said bore within said large piston portion, a third pressure chamber formed between said control valve means and said last named bore, an inlet-outlet port connecting said third pressure chamber alternately to said second inlet conduit and said exhaust chamber, a first passageway to communicate said second pressure chamber with said second inlet conduit, and a second passageway to connect said second pressure chamber with said exhaust chamber, said control valve means operating to close said second passageway and open said first passageway when the fluid pressure supplied to said third pressure chamber through said second inlet conduit and said inlet-outlet port reaches a predetermined value, the operation causing the fluid pressure within said second pressure chamber acting on said large diameter piston portion to urge said small diameter piston portion to amplify the fluid pressure within said first pressure chamber, and said control valve means continuously operating to open said second passageway after connecting said third pressure chamber to said exhaust chamber through said inlet-outlet port.
 2. A hydraulic intensifier as set forth in claim 1, wherein said stepped piston is an integral piston having the small diameter piston portion and the large diameter piston portion formed therein.
 3. A hydraulic intensifier as set forth in claim 1, wherein said stepped piston comprises a small diameter piston and a separate large diameter piston, said small and large diameter pistons being in constant contact with each other.
 4. A hydraulic intensifier as set forth in claim 1, wherein said large diameter piston has a cylinder-shaped shock absorbing member made of resilient material at one end thereof, said cylinder-shaped shock absorbing member being provided with an orifice communicable with said second pressure chamber around the circumference thereof.
 5. A hydraulic intensifier as set forth in claim 1, wherein there is provided at the sides of said large diameter piston an inlet port connecting said second inlet conduit to said third pressure chamber and an exhaust port connecting said exhaust chamber to said third pressure chamber. 